1. Field of the Invention
The present invention relates to a vehicle body drifting suppression device which suppresses a drifting of a vehicle body with respect to a lateral slope of a road surface.
Priority is claimed on Japanese Patent Application No. 2008-129693, filed May 16, 2008, the content of which is incorporated herein by reference.
2. Description of Related Art
To enable safe driving while raining, some roads have lateral slopes on their surface so that rain will not accumulate on the road surface. When a vehicle is running on such a road that has a lateral slope, the vehicle skids towards a lower portion of the road surface. Hereinafter, this phenomenon will be called “vehicle body drifting”.
When vehicle body drifting occurs in this way, a driver's burden of driving the vehicle increases because the driver is forced to adjust the operation of the vehicle by using a steering wheel in order to drive straight without having the vehicle skid towards the lower portion of the road surface.
Consequently, vehicle body drifting suppression devices have been developed, which suppress the drifting of the vehicle body while reducing the driver's burden of driving the vehicle. For example, an electric-powered steering device is known, which increases the control of a steering assist amount when vehicle body drifting is detected, compared to when vehicle body drifting has not occurred (for example, refer to Japanese Unexamined Patent Application, First Publication No. 2007-168617).
In such related vehicle body drifting suppression devices, a steering assist modification amount (a vehicle body drifting suppression control-amount) is defined according to a steering torque amount detected by a steering torque sensor, for the use in the vehicle body drifting restricting control.
Consequently, there was a problem in that the driver senses an unnatural driving feel, when the steering assist modification amount reacted in an exceedingly sensitive manner on the change of the steering torque.
Accordingly, the present invention provides a vehicle body drifting suppression device in which the driver does not sense unnatural driving feel.